1. Field of the Invention
The present invention relates to a radiation image capturing system and a console, and particularly, relates to a radiation image capturing system that performs capturing by using a radiation image capturing apparatus, and displays a preview image on the console based on data transmitted from the radiation image capturing apparatus.
2. Description of Related Art
There have been developed a variety of radiation image capturing apparatuses such as: a so-called direct-type radiation image capturing apparatus that generates electric charges in detection elements according to a dose of an irradiated radiation such as an X-ray, and converts the electric charges into electric signals; and a so-called indirect-type radiation image capturing apparatus that converts the irradiated radiation into electromagnetic waves with another wavelength, such as visible light, by a scintillator and the like, thereafter, generates electric charges by photoelectric conversion elements such as photodiodes according to energy of the electromagnetic waves thus converted and irradiated, and converts the generated electric charges into electric signals (that is, image data). Note that, in the present invention, the detection elements in the direct-type radiation image capturing apparatus and the photoelectric conversion elements in the indirect-type radiation image capturing apparatus are collectively referred to as radiation detection elements.
This type of radiation image capturing apparatus is known as a flat panel detector (FPD), and heretofore, has been composed as a so-called dedicated type integrally formed with a supporting table (for example, refer to Japanese Patent Application Laid-Open Publication No. H09-73144). However, in recent years, a portable-type radiation image capturing apparatus, which has radiation detection elements and the like housed in a cabinet thereof, and is made portable, has been developed and put into practical use (for example, refer to Japanese Patent Application Laid-Open Publication No. 2006-058124 and Japanese Patent Application Laid-Open Publication H06-342099).
Usually, the radiation image capturing apparatus is composed in such a manner that a plurality of radiation detection elements 7 are arrayed in a two-dimensional shape (matrix shape) on a detection unit P, and that switch units formed of thin film transistors (hereinafter, referred to as TFTs) 8 are each connected to the respective radiation detection elements 7.
Then, usually, radiation image capturing is performed in such a manner that the radiation is irradiated onto the radiation image capturing apparatus from a radiation source of a radiation generation device through a body or the like of a capturing target person, that is, a subject. Then, after the capturing, an ON voltage is applied from a gate driver 15b sequentially to the respective lines L1 to Lx of scanning lines 5, the respective TFTs 8 are sequentially turned to an ON state, the electric charges generated and accumulated in the respective radiation detection elements 7 by the irradiation of the radiation are sequentially discharged to the respective signal lines 6, and the discharged electric charges are each read out as image data D in the respective readout circuits 17.
Incidentally, in the conventional radiation image capturing system using the radiation image capturing apparatus as described above, the radiation image capturing has been performed by transferring signals between the radiation image capturing apparatus and the radiation generation device. However, for example, in such a case where manufacturers of the radiation image capturing apparatus and the radiation generation device are different from each other, it is not always easy to construct an interface therebetween, or alternatively, the interface cannot be constructed.
In such a case, when viewed from the radiation image capturing apparatus side, it is not understood at which timing the radiation is to be irradiated from the radiation source. Therefore, in such a case, it is necessary that the radiation image capturing apparatus be configured so as to be capable of detecting that the radiation is irradiated from the radiation source by the apparatus itself. Then, there are developed a variety of such radiation image capturing apparatuses, each of which is capable of detecting a start of the radiation irradiation by the radiation image capturing apparatus itself and then capable of performing the capturing as described above.
For example, in the inventions described in U.S. Pat. No. 7,211,803 and Japanese Patent Application Laid-Open Publication No. 2009-219538, the following is proposed. When the radiation irradiation onto the radiation image capturing apparatus is started and the electric charges are generated in the respective radiation detection elements 7, the electric charges flow out from the respective radiation detection elements 7 to bias lines 9 (refer to FIG. 3 and the like, which will be described later) connected to the respective radiation detection elements 7, and currents flowing through the bias lines 9 are increased. By using this phenomenon, values of the currents flowing through the bias lines 9 are detected by providing a current detecting unit in the bias lines 9, and based on the values of the currents, the start of the radiation irradiation, and the like are detected.
Moreover, the inventors of the present invention repeated a variety of researches for other methods of detecting the irradiation of the radiation by the radiation image capturing apparatus itself. As a result, the inventors were able to find out some methods capable of accurately detecting the irradiation of the radiation by the radiation image capturing apparatus itself (for example, refer to Pamphlet of International Publication No. WO2011/135917, and Pamphlet of International Publication No. WO2011/152093). These new detection methods will be described later in detail.
Then, the radiation image capturing system using the radiation image capturing apparatus as described above is frequently configured so as to extract data for a preview image (hereinafter, preview image data) from among image data D captured by the radiation image capturing apparatus and transmit the extracted data to a console 58 (refer to FIGS. 6 and 7 to be described later) in order to confirm whether or not the subject is appropriately captured by the radiation image capturing apparatus.
In that case, the console 58 is configured, when the preview image data is transmitted thereto from the radiation image capturing apparatus, so as to create a preview image based on the transmitted preview image, and to display the preview image on a display unit thereof. Then, an operator such as a radiographer confirms the preview image concerned, and determines whether or not re-capturing is necessary, and so on.
Incidentally, in the case of configuring the radiation image capturing apparatus so as to detect the start of the radiation irradiation by itself as described above, since the interface is not constructed with the radiation generation device, a state where the radiation irradiation is started is brought during a period while reset processing for the respective radiation detection elements 7 and later-described readout processing for image data d for detecting the start of the irradiation are performed before the radiation image capturing in the radiation image capturing apparatus.
Therefore, in some cases, the radiation irradiation is started at the point of time when the ON voltage is applied to a scanning line 5 in a portion other than a terminal end portion of a detection unit P in which the radiation detection elements 7 are two-dimensionally arrayed, and when the reset processing for the respective radiation detection elements 7, and the like are performed.
Then, in such a case, for the purpose of equalizing a time of leaving the respective TFTs 8 in an OFF state (that is, the time is an effective accumulation time Tac (refer to FIG. 15 to be described later) among the respective scanning lines 5 before performing the readout processing for the image data D, a configuration is sometimes adopted so that the readout processing for the image data D can be performed not by starting the application of the ON voltage from the scanning line 5 (for example, a line L1 or Lx of the scanning line 5 in FIG. 3) at the terminal end portion of the detection unit P, but by starting the application of the ON voltage from a scanning line 5 to which the ON voltage should be applied after a scanning line 5 to which the ON voltage is applied at the point of time when the start of the radiation irradiation is detected or immediately before the point of time concerned.
However, the following is gradually found out. In the case of adopting such a configuration, if the preview image data is not processed appropriately, then as shown in FIG. 23 for example, a brightness difference sometimes appears at a portion of such a scanning line 5 (hereinafter, referred to as a readout starting line Ls) to which the ON voltage is first applied at the point of time when the readout processing for the image data D is started, the portion belonging to the created and displayed preview image p_pre.
Then, when the brightness difference as described above appears in the preview image p_pre, there occurs a problem that it becomes difficult to carry out confirmation work for the preview image p_pre, which is as described above, by the operator such as the radiographer, and determination processing as to whether or not the re-capturing is necessary, the determination processing being based on the confirmation work.
Moreover, in the case of performing image correction, which is precise and requires labor, in order to perform image correction for the brightness difference that appears in the preview image p_pre, there is also a problem that, since it takes time to display the preview image p_pre subjected to the image correction an operator's request that the preview image p-pre be confirmed earlier and the determination as to whether or not the re-capturing is necessary be thereby performed earlier becomes unsatisfied.